mwavepy.network | index /usr/local/lib/python2.6/dist-packages/mwavepy/network.py

`Provides the Network class and related functions.`

Modules
`` |  |
mwavepy.mathFunctions numpy | os pylab | scipy.stats mwavepy.touchstone |

Classes
`` |  | __builtin__.object Network
class Network(__builtin__.object)
`` | `Represents a n-port microwave network. the most fundemental properties are: s: scattering matrix. a kxnxn complex matrix where 'n' is number of ports of network. z0: characteristic impedance f: frequency vector in Hz. see also frequency, which is a Frequency object (see help on this class for more info) The following operators are defined as follows: '+' : element-wise addition of the s-matrix '-' : element-wise subtraction of the s-matrix '*' : element-wise multiplication of the s-matrix '/' : element-wise division of the s-matrix '**': cascading of two networks '//': de-embdeding of one network from the other. various other network properties are accesable as well as plotting routines are also defined for convenience, most properties are derived from the specifications given for touchstone files.`
| Methods defined here: __add__(self, other) `element-wise addition of s-matrix` __div__(self, other) `element-wise complex division of s-matrix` __eq__(self, other) __floordiv__(self, other) `implements de-embeding another network[s], from this network see de_embed` __getitem__(self, key) `returns a Network object at a given single frequency` __init__(self, touchstone_file=None, name=None) `constructor. takes: file: if given will load information from touchstone file name: name of this network.` __mul__(self, a) `element-wise complex multiplication of s-matrix` __ne__(self, other) __pow__(self, other) `implements cascading this network with another network` __sub__(self, other) `element-wise subtraction of s-matrix` add_noise_polar(self, mag_dev, phase_dev, **kwargs) `adds a complex zero-mean gaussian white-noise signal of given standard deviations for magnitude and phase takes: mag_mag: standard deviation of magnitude phase_dev: standard deviation of phase [in degrees] n_ports: number of ports. defualt to 1 returns: nothing` change_frequency(self, new_frequency, **kwargs) flip(self) `swaps the ports of a two port` interpolate(self, new_frequency, **kwargs) `calculates an interpolated network. defualt interpolation type is linear. see notes about other interpolation types takes: new_frequency: **kwargs: passed to scipy.interpolate.interp1d initializer. returns: result: an interpolated Network note: usefule keyward for scipy.interpolate.interp1d: kind : str or int Specifies the kind of interpolation as a string ('linear', 'nearest', 'zero', 'slinear', 'quadratic, 'cubic') or as an integer specifying the order of the spline interpolator to use.` multiply_noise(self, mag_dev, phase_dev, **kwargs) `multiplys a complex bivariate gaussian white-noise signal of given standard deviations for magnitude and phase. magnitude mean is 1, phase mean is 0 takes: mag_dev: standard deviation of magnitude phase_dev: standard deviation of phase [in degrees] n_ports: number of ports. defualt to 1 returns: nothing` nudge(self, amount=9.9999999999999998e-13) `perturb s-parameters by small amount. this is usefule to work-around numerical bugs. takes: amount: amount to add to s parameters returns: na` plot_polar_generic(self, attribute_r, attribute_theta, m=0, n=0, ax=None, show_legend=True, **kwargs) `generic plotting function for plotting a Network's attribute in polar form takes:` plot_s_all_db(self, ax=None, show_legend=True, **kwargs) `plots all s parameters in log magnitude takes: ax - matplotlib.axes object to plot on, used in case you want to update an existing plot. show_legend: boolean, to turn legend show legend of not **kwargs - passed to the matplotlib.plot command` plot_s_db(self, m=None, n=None, ax=None, show_legend=True, **kwargs) `plots the magnitude of the scattering parameter of indecies m, n in log magnitude takes: m - first index, int n - second indext, int ax - matplotlib.axes object to plot on, used in case you want to update an existing plot. show_legend: boolean, to turn legend show legend of not **kwargs - passed to the matplotlib.plot command` plot_s_deg(self, m=None, n=None, ax=None, show_legend=True, **kwargs) `plots the phase of a scattering parameter of indecies m, n in degrees takes: m - first index, int n - second indext, int ax - matplotlib.axes object to plot on, used in case you want to update an existing plot. show_legend: boolean, to turn legend show legend of not **kwargs - passed to the matplotlib.plot command` plot_s_deg_unwrapped(self, m=None, n=None, ax=None, show_legend=True, **kwargs) `plots the phase of a scattering parameter of indecies m, n in unwrapped degrees takes: m - first index, int n - second indext, int ax - matplotlib.axes object to plot on, used in case you want to update an existing plot. show_legend: boolean, to turn legend show legend of not **kwargs - passed to the matplotlib.plot command` plot_s_mag(self, m=None, n=None, ax=None, show_legend=True, **kwargs) `plots the magnitude of a scattering parameter of indecies m, n not in magnitude takes: m - first index, int n - second indext, int ax - matplotlib.axes object to plot on, used in case you want to update an existing plot. show_legend: boolean, to turn legend show legend of not **kwargs - passed to the matplotlib.plot command` plot_s_polar(self, m=0, n=0, ax=None, show_legend=True, **kwargs) `plots the scattering parameter of indecies m, n in polar form takes: m - first index, int n - second indext, int ax - matplotlib.axes object to plot on, used in case you want to update an existing plot. show_legend: boolean, to turn legend show legend of not **kwargs - passed to the matplotlib.plot command` plot_s_rad(self, m=None, n=None, ax=None, show_legend=True, **kwargs) `plots the phase of a scattering parameter of indecies m, n in radians takes: m - first index, int n - second indext, int ax - matplotlib.axes object to plot on, used in case you want to update an existing plot. show_legend: boolean, to turn legend show legend of not **kwargs - passed to the matplotlib.plot command` plot_s_rad_unwrapped(self, m=None, n=None, ax=None, show_legend=True, **kwargs) `plots the phase of a scattering parameter of indecies m, n in unwrapped radians takes: m - first index, int n - second indext, int ax - matplotlib.axes object to plot on, used in case you want to update an existing plot. show_legend: boolean, to turn legend show legend of not **kwargs - passed to the matplotlib.plot command` plot_s_smith(self, m=None, n=None, r=1, ax=None, show_legend=True, **kwargs) `plots the scattering parameter of indecies m, n on smith chart takes: m - first index, int n - second indext, int r - radius of smith chart ax - matplotlib.axes object to plot on, used in case you want to update an existing plot. show_legend: boolean, to turn legend show legend of not **kwargs - passed to the matplotlib.plot command` plot_vs_frequency_generic(self, attribute, y_label=None, m=None, n=None, ax=None, show_legend=True, **kwargs) `generic plotting function for plotting a Network's attribute vs frequency. takes:` read_touchstone(self, filename) `loads values from a touchstone file. takes: filename - touchstone file name, string. note: ONLY 'S' FORMAT SUPORTED AT THE MOMENT all work is tone in the touchstone class.` write_touchstone(self, filename=None) `write a touchstone file representing this network. the only format supported at the moment is : HZ S RI takes: filename - filename (not including extension) note: in the future could make possible use of the touchtone class, but at the moment this would not provide any benefit as it has not set_ functions.` Data descriptors defined here: __dict__ `dictionary for instance variables (if defined)` __weakref__ `list of weak references to the object (if defined)` f `the frequency vector for the network, in Hz.` frequency `returns a Frequency object, see frequency.py` inv `a network representing inverse s-parameters, for de-embeding` number_of_ports `the number of ports the network has.` passivity `returns passivity metric for a multi-port network. mathmatically, this is a test for unitary-ness. for two port this is ( |S11|^2 + |S21|^2, |S22|^2+|S12|^2) in general it is S.H * S where H is conjugate transpose of S, and * is dot product http://en.wikipedia.org/wiki/Scattering_parameters#Lossless_networks` s `The scattering parameter matrix. s-matrix has shape fxmxn, where; f is frequency axis and, m and n are port indicies` s11 s12 s21 s22 s_db `returns the magnitude of the s-parameters, in dB note: dB is calculated by 20*log10(|s|)` s_deg `returns the phase of the s-parameters, in radians` s_deg_unwrap `returns the unwrapped phase of the s-paramerts, in degrees` s_mag `returns the magnitude of the s-parameters.` s_rad `returns the phase of the s-parameters, in radians.` s_rad_unwrap `returns the unwrapped phase of the s-parameters, in radians.` t `returns the t-parameters, which are also known as wave cascading matrix.` y z0 `the characteristic impedance of the network.`

Functions
`` |  | average(list_of_networks) `calculates the average network from a list of Networks. this is complex average of the s-parameters for a list of Networks takes: list_of_networks: a list of Networks returns: ntwk: the resultant averaged Network` cascade(a, b) `cascade two s-matricies together. a's port 2 == b's port 1 if you want a different port configuration use the flip() fuction takes: a: a 2x2 or kx2x2 s-matrix b: a 2x2, kx2x2, 1x1, or kx1x1 s-matrix note: BE AWARE! this relies on s2t function which has a inf problem if s11 or s22 is 1.` de_embed(a, b) `de-embed a 2x2 s-matrix from another 2x2 s-matrix c = b**-1 * a note: BE AWARE! this relies on s2t function which has a inf problem if s11 or s22 is 1.` flip(a) `invert the ports of a networks s-matrix, 'flipping' it over note: only works for 2-ports at the moment` inv(s) `inverse s-parameters, used for de-embeding` one_port_2_two_port(ntwk) `calculates the two-port network given a symetric, reciprocal and lossless one-port network. takes: ntwk: a symetric, reciprocal and lossless one-port network. returns: ntwk: the resultant two-port Network` psd2_2_time_domain() `This would be very useful i need to do this` s2t(s) `converts a scattering parameters to 'wave cascading parameters' input matrix shape should be should be 2x2, or kx2x2 BUG: if s -matrix has ones for reflection, thsi will produce inf's you cant cascade a matrix like this anyway, but we should handle it better` t2s(t) `converts a 'wave cascading parameters' to scattering parameters input matrix shape should be should be 2x2, or kx2x2`

Data
`` |  | ALMOST_ZER0 = 9.9999999999999995e-07